The rapid expansion of the use of information technology in clinical practice settings has the potential to profoundly affect the delivery of health care. Regional and statewide immunization information systems (IISs) have developed over a number of years and have the capability to provide significant benefits in terms of immunization delivery for primary care practices that use the varied functions that they offer. However, little is known about how extensively clinical practices presently use IISs, how much they understand the functions that an IIS offers, and what barriers they encounter to using various IIS functions. In parallel to the expansion of immunization information systems, there has been a tremendous push for practices to adopt electronic health records (EHRs). EHR systems generally track immunizations and, in many cases, can electronically transfer immunization records to immunization information systems. As EHR functionality increases further and bi-directional data flow between EHRs and immunization information systems becomes the norm, many EHRs will likely also be able to tap into immunization information systems to gather practice-level immunization reports. This project will address a number of issues related to the extent of healthcare practices'training in and use of the features of a statewide IIS, will examine a novel IIS training modality, and will be among the first studies to evaluate how an IIS is used in clinical practices that have EHRs. This project will also provide important new information that will be of significant value in identifying future research priorities related to the confluence of data capabilities that will result from expanded interconnectivity between EHRs and immunization information systems.